Effective lubrication is necessary to maintain efficient and prolonged operation of equipment having bearings and other wear parts. To ensure effective lubrication, it is important to monitor whether lubricant is being properly delivered to such equipment and, if not, to alert an operator so that corrective action can be a taken before the equipment is damaged or fails.
One system that has been proposed for monitoring fluid is disclosed in U.S. Pat. No. 4,642,614 to Cook, incorporated herein by reference. The Cook patent discloses a fluid flow monitoring system for monitoring intermittent flow of lubricant through lubricant lines. The monitoring system includes signal lights for indicating to the operator the various conditions of the system. A thermistor in the line of flow indicates the occurrence of lubricant flow based on the temperature of the thermistor. A cooling of the thermistor signals that lubricant is flowing through the line, and a heated thermistor temperature signals a fault condition where lubricant is not flowing.
Although conventional fluid flow monitoring systems are capable of monitoring lubricant flow in a lubricant line, there is a need for a more sensitive and durable mechanism for detecting fluid flow and for providing a more accurate and reliable indication of a fault condition in a lubricant line.